arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2602.06387cond-mat.str-el
收藏

费米子方法用于S=1/2 XX杂化三聚体-双聚体链中基态激发和磁化平台

Fermionic Approach to Elementary Excitations and Magnetization Plateaus in an S=1/2 XX Hybrid Trimer-Dimer Chain

Solid State Physics Division, Bhabha Atomic Research Centre(固体物理部,巴哈原子研究中心);Homi Bhabha National Institute(霍米·巴巴国立研究所)

K. S. Chikara, A. K. Bera, A. Kumar, S. M. Yusuf

AI总结:

本文通过费米子方法研究S=1/2 XX杂化三聚体-双聚体链中的基态激发和磁化平台,揭示了磁化平台与全局周期性相关,扩展了OYA条件至簇链结构。

摘要:

我们研究了一个由三聚体-双聚体单元(J1-J1-J2-J3-J2拓扑结构)组成的二维自旋1/2 XX链在横向磁场h下的基态激发和磁化。利用格林函数理论和约尔丹-威格纳变换,我们将系统映射到无自旋费米子,并关注反铁磁(AFM)相互作用。在零温度下,出现不同的1/5和3/5磁化平台,由全局周期性Q=5决定,磁化平台的数量与无自旋费米子费米能级以上的激发间隙数量一致。磁相图在(h-Js)平面中包含朗金液体(LL)态、无能隙反铁磁态、两个磁化平台态和一个完全极化的有能隙磁态。LL和无能隙反铁磁相的宽度与相应基态激发的带宽gamma = |E(k=0)-E(k=pi)|成正比,而磁化平台态的宽度由激发间隙决定。我们的研究为利用中子散射等实验技术以及量子蒙特卡罗(QMC)和密度矩阵重整化群(DMRG)等理论和数值方法探索相互作用的三聚体-双聚体自旋链开辟了新方向。此外,我们将Oshikawa-Yamanaka-Affleck(OYA)条件扩展到一般化的簇链,证明允许的磁化平台由链的全局周期性(例如,三聚体-双聚体链的Q=5)决定,而不是由单个单元的局部周期性(三聚体的Q=3或双聚体的Q=2)决定。

英文摘要:

We study the elementary excitations and magnetization of a one-dimensional spin-1/2 XX chain comprising trimer-dimer units (the J1-J1-J2-J3-J2 topology) under a transverse magnetic field h. Using Green's function theory and the Jordan-Wigner transformation, we map the system onto spinless fermions and focus on antiferromagnetic (AFM) interactions. At zero temperature, distinct 1/5 and 3/5 magnetization plateaus emerge, determined by the global periodicity Q=5, with the number of plateaus matching the number of excitation gaps above the Fermi level of the spinless fermions. The magnetic phase diagram in the (h-Js) plane features a Luttinger liquid (LL) state, a gapless AFM state, two magnetization plateau states, and a fully polarized gapped magnetic state. The widths of the LL and gapless AFM phases are found to be proportional to the bandwidths gamma = |E(k=0)-E(k=pi)| of the corresponding elementary excitations, whereas the widths of the magnetization plateau states are governed by the excitation gaps. Our study opens new directions for exploring interacting trimer-dimer spin chains in quantum magnetism using experimental techniques such as neutron scattering, as well as theoretical and numerical approaches including quantum Monte Carlo (QMC) and density-matrix renormalization group (DMRG) methods. Furthermore, we extend the Oshikawa-Yamanaka-Affleck (OYA) condition to generalized cluster chains, demonstrating that the allowed magnetization plateaus are governed by the global periodicity of the chain (e.g., Q=5 for a trimer-dimer chain), rather than by the local periodicity of individual units (Q=3 for a trimer or Q=2 for a dimer).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑